The University of Virginia (UVa) Schools of Medicine and Engineering have a multitude of established, successful research programs focused on development of medical-imaging techniques for a wide spectrum of diseases. Translational pulmonary-disease research using magnetic resonance (MR) imaging is carried out at the UVa Center for In-vivo Hyperpolarized Gas MR Imaging, where the hyperpolarized noble gases, helium-3 (He-3) and xenon-129 (Xe-129), are used as inhaled contrast agents to provide MR images of the lung with high spatial and temporal resolution. This Center, established in the Department of Radiology & Medical Imaging in 2000, houses three state-of-the-art whole-body clinical MR scanners and two He-3 gas-polarization systems. To date, we have performed over 200 human studies with hyperpolarized Xe-129 and over 1200 human studies with hyperpolarized He-3, which is the largest series of such studies by a single institution. While much of the early work with hyperpolarized-gas MRI was done with He-3, the current consensus in the field is that Xe-129 is the future of the field due to the expense and relative scarcity of e-3. Besides wide availability and low cost compared with He-3, the intrinsic properties of Xe-129 permit acquisition of not only the same structural and functional information provided by He-3 imaging, but also new physiological information that cannot be obtained with any other medical-imaging technique. Since our institution does not have a gas-polarization system dedicated for hyperpolarized Xe-129 production, we are requesting funds to purchase a state-of-the-art, high-performance Xe-129 gas polarizer, which would substantially enhance our ability to continue pioneering research in hyperpolarized-gas pulmonary imaging. We propose to purchase the XeBox-B10, a Xe-129 polarization system from Xemed, LLC, capable of producing hyperpolarized Xe-129 at a rate of ten liters/hour at a polarization of 50%. Currently, in order to conduct Xe-129 MR studies at our Center, we have a contract with Xemed LLC through which we share with other institutions a XeBox-H10 system, which is an older model with an output of four liters of Xe-129 per hour at a polarization of 35-40%. With the current arrangement, we are dependent on the schedules of the other institutions that have similar contracts with Xemed. The three main benefits of purchasing the proposed new system will be: 1) more polarized Xe- 129 gas per hour, which will allow us to decrease study duration, increasing patient comfort and compliance, and decreasing the cost per study; 2) improved subject recruitment and an increase in the number of studies per year, since we will have a polarizer in our Center full time; and 3) higher gas polarization, which will directly increase the signal from the dissolved-phase component of Xe-129, thereby improving imaging quality. The increased signal can also be traded for an increase in spatial resolution of the MR images, providing better regional depiction of heterogeneous lung disease. Full utilization of the enhanced capabilities afforded by the new XeBox-B10 system will be assured through a comprehensive administrative, technical and scientific plan.